RESUMEN
<p><b>BACKGROUND</b>Nerve growth factor (NGF) is well-known for its important role in the development and maintenance of the nervous system. Along with its neurotrophic role, NGF has been detected in the testis of mouse, rat and human, suggesting an additional non-neurotrophic effect in the male reproductive system. The expression of β-NGF in the undescended testes (cryptorchidism) has not been detected at present. The aim of this study was to evaluate the expression of β-nerve growth factor mRNA and protein in experimental cryptorchidism.</p><p><b>METHODS</b>A unilateral mechanical cryptorchidism model in the Sprague-Dawley rat was established and the expression of β-NGF with histologic changes in experimental cryptorchidism were investigated using one step quantitative real-time reverse transcription-polymerase chain reaction, in situ hybridization histochemistry, immunofluorescence and hematoxylin-eosin staining.</p><p><b>RESULTS</b>The expression of β-NGF mRNA and protein were both significantly decreased in the development of unmarred testis and cryptorchidism-induced testis, and the decrease of β-NGF in cryptorchidism-induced testis was far greater than that in uninjured testis.</p><p><b>CONCLUSION</b>From this investigation, we confirmed a lower expression of β-NGF in undescended testes than in the development of testis.</p>